Drive for limit switches and the like



y 1 1932- H: VQHARDING 1,867,453

DRIVE FOR LIMI'I SWITCHES AND THE LIKE Filed May 27. '1927 s Sheets-Sheet} 1 lllllllllllfllll lllllllllllllll Jzazmi'd rfzaniu g w m ATTORNEY;-

July 12, 1932. H. v. HARDING DRIVE FOR LIMIT SWITCHES AND THE LIKE Filed May 27 192-1 3 Sheets-Sheet 2 Jfdwam? EJfar' ATTORN EY July 12, 1932. H. v. HARDING 1,867,453

DRIVE FOR LIMIT SWITCHES AND THE LIKE Filed May 2'7, 1927 3 Sheets-Sheet 3 21:] REVERJE L Famwim l [MIT SWITCH TO 57b! REVEKJC DIRECT/DIV wing/:3] 64 yn 3 u u 26 JOLEND/D BRAKE can -r 3 pento;

MOTOR (Ittorneg Patented July 12, 1932' vireo STATES PATENT ries HOWARD v. HARDING, on Hansonum; YORK, .ASSIGNOR ToerrroRD-wooniooiu-j PANY, or ,I-IUDSON ,.1\TE

w, Yon-K; A coitroanrioivor NEW. .YORK

DRIVE FOR LIMIT swrrcnns; AND Q THE LIKE Application filed May 27,

This inventionrelates to driving mechanism of the speed reducer type, useful for-- driving limit switches and the like; and among other objects, the invention aims to provide a driving mechanism-which maybe: adjusted both initially, to suit conditions at an installation, and after use, to correct errors; also a drive for an indicator so con structed and arranged that the indicator may be adjusted simultaneously with the driving mechanism. The invention provides a slowly driven member which'may be used to actuate a series of limit switches controlling the hoisting and/or traverse movements of a trolley bucket or the like.

In the pendingapplication of H-LE. Hallenbeck, Ser. No. 491,534, filed October 27, 1930, assigned to the assignee of thisapplication, the device of the present invention is shown slightly modified so as to control both the hoist and trolley units, and .the necessary wiring and electrical control apparatus are also shown therein. n

The accompanying drawings show a pre-- -ferred embodiment of the invention."

In the drawings: I

Fig. 1 is an elevation of a-,trolley unit, with a slow-speed drive which embodies the invention arranged to actuatelimit switches controlling the motor of the unit;

Fig. 21's an-elevation on an enlarged scale of the slow-speed driving mechanism, viewed from the left side otFig'. 1

Fig. 3 is a side elevation of the same; 7 Fig. 4 is a section on line 4l of Fig. 3; ig. 5 is a section on line 55 of Fig. 2; Fig 6 is a diagram showing how the mechanism is connected to the indicator;

Fig. 7 is a top plan View of the trolley unit shown in Fig; 1, omitting thetrolley rope and the limit switch actuator, bu the solenoid brake;'and

Fig. 8 is a wiring diagram.

In Fig. 1 the illustrative unit shown is aj trolley unit, for movingthe trolley of a traversing hoist back and forth along a track; and comprises a base 10, a motor 11, a grooved drum 12 geared to the motor, an idler drum 18 likewise grooved and a trolley rope 14; which extends to the trolley (not shown) t showing ly mounted on but ada 1927. Serial No. 194,842.

no slip of the trolley rope I on-the idler and therefore, adjustments need 6 1 be made-very infrequently to have the limit 1 switchesstop the motor at the proper times. I The limit switch actuating mechanism:-

shown in the drawings is mounted on a brack V 7 et- 15 (Fig. 1 adjacent to the idler drum 1 3 and is driven from theshaft of saiddrum by a sprocket chain 16, the sprockets 17,?18 being selected to givethedesired reduction of speed between theshafts 19 and 20 to suit the'installation Obviously a long traverse (or ahighhoist) will require a greater redu'ctio'n than a short one if the same stand-'- ardized mechanism is tobe: used for all in- V stallations. V The limit switch driving mechanism specifi cally comprises two rotary cams 21, 22 loosepted to be frictionally clutched to the shaft 23, which is driven-by worm gearing 24 from the shaft 20, See Figsfli: and 5. The two'limit switches 25, 26 are preferably mount'ed on the housing'27 which supports the driving mechanismand are of standard construction, being so madeas to open'the circuit e f-the motor 11 whenever either of the cam projections 21a, 22a comes in contact with the corresponding limit switch roller 25a, 26a. As soon asthe mo-' tor circuit is opened, the motor is a solenoid brake ;S, (Fig.

brings the trolley rope 14 to'rest, resulting;- in stopping of the trolley and the depending bucket or other hoist'means.

7 which quickly 1 stopped by It is highly desirable that both the limit switches and the indicator be-adjustable so as to be accurate. Ifthe indicator is inaccurate, I

the operator (whois usually so placed that he cannotsee the bucket) will be unable to lower the bucket-at the desired point: This will result ininjury to the'bucket as, for example, if it strikes against a concrete wall.

The limit switches must act at the proper times, else the bucket either will be stopped too soon or not soon enough. If the bucket is stoppedtoo soon, the operator may not be able to lower it at the desired point for discharge of its load or for taking on a new load; or, if the bucket is lowered, it may crash into a bin wall or other obstruction. If the bucket is not stopped soon enough, it willp robably craslrinto a wall or into the superstructure which supports the elevated track along which the bucket travels, resulting in serious damageto the bucket and probable shut-down r 'of the plant. It is also ,highly desirable to adjust the limit switch actuating mechanism and the indicator simultaneously words, to correct anyerrorsin each to the same extent and at the same time. By the present invention 1 accomplish :these desiderata To facilitate adjustment of the limit switch actuating means, I provide the cams 21-, 22 in the form of circular plates or disks each.

7 of which is dishedand beveled (Fig. 5). In

cl'ampedgon the plate threaded on the end cone 29 is keyed; to the shaft 23 so as to be]? the description to follow, butone of the cams and associated parts will be described, since both sides of the mechanism are alike; The camlplate 2l'receives a soft metal annulus V 28,1(Fig. 5) which is carried by a cone 29 21 by g aname screw-,-

of the shaft/-23. The

rotated thereby,1and has abeveled periphery to fit'th'e beveled surface provided on. the

gdished'lcam plate 21, thus driving cam plate 21' when the nut SOistightenedQ 'By looseningtheg'nut 30 the cone is freed from frictiony al V-engagement "with: the surrounding cam plate 21 and the cam plate 21 may then be ma -turned on shaft 23. relativeto' the'cone 29.

To facilitate nice adjustment of the cam plate 21, it may'have a radial notch 31 (Fig. 2) in the'central part of the cam enlargementjQla; and when the mechanism is set to operate properly fora particular.installation,at the time the installation is first put in use, a mark may-be cut in the outer surface of the soft metal annulus 28', said mark being alined with the notch 31. Then the same adjustment will be made withthe other annulus andcam. It'is necessary to make adjustments of the 1 same degree'on both sides of the mechanism, as thebucket or other hoisting means travels thefsame distance in both directions and any correction made to govern thetravelflin one; d rection must also be jmade to govern the Y travel in the opposite direction. I

H-V'After the installation has been fllirusi for a time, 'dueto; the cumulative'eff'ect ofregpeateduslight" slippage ofthe trolley rope 14,011 the idler 13, the vlimit switches may stop'themotor too soon-whenthe bucketiis golng 111 one direction-and not soon enough when the bucketis moving in the opposite dlIGCillOIl' 7 An ad ustment, is 7 now Enecessary or in other and may be easily effected by'loosening one of the nuts30 and moving the cam plate around to the desiredextent. The soft metal annulus 28 may be easily scratched to indicatethe new setting which is to be tested. If the new settingis unsatisfactory, a further trial may be made. When the proper adjustmentis made on one side of the mechanism, exactly the same adjustment maybe obtained on the other side by measuring from the initial markto the last mark made on the soft metal annulus. This measurement may be made conveniently by calipers or diyiders. When both adjustments are exactly the same, as theyshould be, the bucket or exactly the right point, when traveling in bothxdirections;

The described adjustment must be made because of-movement of the rope 14 relative to the drum-13; Such movement is usually cumulative in effect becauseof sudden stoppage of a loaded bucket continually being j moved inone direction only, the bucket usually traveling empty in the opposite direction. ;However, there is a further adjustment desirable and in some instances necessary, d-ue'to what is known as creepage of 7 other material handling means will stop at a the rope. :Thiscreepagevpis believed to be due to the wear of the rope and also to wear 1 of the grooves in theTd-rum andmay possis blyr be: due to a slight untwisting of the;

strands o fthe wire rope. Whatever the cause oricauses of the creepage, it cannot be prevented any-known means. 7 Hence, I have provided a further adjustment by permittin :the softv metal annulus 28 to be moved rela' f tive tothe cone which carries it. 'As shown 7 in Figs.v2 and 5, the annulus 28 has a tapered inner" surface:-frictionally engaging the, frusto-conical surface provided on a boss 32 integral with-the cone 29. Screws 33 are used to clamp the annulus 28 to the cone with, washers 34, interposed between the 7 screws and the annulus. To permit the operator to measure the extent of this secondary adjustment, small'scales may be fixed adj acent each other to the annulus and boss, as

indicated in Fig, 2.1 l

While an indicator is not necessary, it is usually highly desirable, particularly when the hoistis'operated by one man who is not in a position to see the bucket at all times. .If, an indicator is used,- it is best driven from the Cami For this reason each'annulus 28- l may have an annular groove35to receive a and descend to receive and discharge its.

loads.- Whenthe pointer .comes oppositeone ofthe indicia 41, the operator will bring the bucketto rest by shutting offthe current to the motor, and will then hoist or lower the bucket. It will be clear thatas the annulus 28 isalways secured to the cone29, which is keyed to the shaft 23, the indicator pointer will have no movement relative to the shaft except when the described adjustment for 1 creepage is made. This is as it should be because when the hunt switch driving'means is not properly ad usted because of creepage the indicator is also out of adjustment,-

and should be moved to the'same extent.

The specificindicator shown in Fig.6 is described and claimed in my Patent No. 1,705,973.

WVhen the bucket or other material-carrier ,is to be moved horizontally in its traverse,

the operator moves the drum switch shown in Fig. 8 (or closes some other standard form of switch) thus completing the-motor circuit. The magnet of the solenoid brake S immediately pulls apart the brake shoes, in

shown) by whichthe trolleyis supported.

Rotation of idler drum 13 eifectsanextremely slow oscillation (partial revolution) of slow speed shaft 23, and hence ofcam plates 21, 22. One of the cams, say cam 21, is'so arranged angularly with respect to shaft 23 that it comes in contact :with roller 25* of limit switch '25 ,shortly before the bucket reaches the desired limitof travel (which limit may be over one of a series of bins, or over a storage pile or over .a pit or; pocket in which the bucket is loaded). Asthe limit switch opens, the motor circuit is opened, as

will be clear from Fig. 8; and when the circuit is open, the magnetic coils of the solenoid brake S are de-energized, whereupon the armature shaft of the motor is braked and the motor, drums, rope, trolley and bucket are quickly brought to rest. After an interval of lowering and hoisting, traverse'is resumed, but nowin the other direction, and this time the other cam22 opens the other limit switch '26. 7

t will be clear that while only one limit switch is shown actuated by each'cam, more than one may be so'actuated, as shown in the above-indentified Hallenbeck application. Also the limit switches 25, 26 and/or their duplicates may be used to control hoisting as well .as traverse movements and otherwise maygovern the operation of a other material-handlingelement. j

Obviously. the present invention is not restricted'to the particular embodiment thereof hereinshown and described. Moreover, it

bucket or is not indispensable that all the features of the invention be used conjointly, since they.

may beemployed advantageously in various combinations and subcombinations.

What I. claim is 1- 1. A traversingjhoist comprising, in combination, a motor; a drum driven by the motor; a second drum on a countershaft; a' traverse rope woundabout both drums and driving the second drum; a set of limit switches connected in the motor circuit;

means drivenb-y the shaft of the second drum for actuating the limit switches; an indicator constructed and arranged to indicate the traverse of the rope; and connections between the indicator and the limit switch. actuating means, said connections being so constructed and arranged that adjustment of saidfactuating parts also properly adjusts-the indicator. v J

,2. A traversing hoist, comprising, in combination, a -mo'tor;'a grooved drum driven V by the motor a second grooved drum on a counter-shaft; a traverseropewound about both dr'ums and driving the second. drum; a

set of limit switches-connected in the motor circuit; means driven by the shaft of the second drum for actuating the limit switches; means to adjust said limit switch actuating means; and an indicator driven from the means for actuating the limit" switches so that when the adjustment of the corresponding limitiswitchactuating means is made, the r indicator willbe adjusted to an equal extent.

3.- A; traversinghoist comprisingin com-- biuation, a power-actuated traverserope con-; nectedto'the material-handling element of the traversin'g'hoist; a speed-reduoing.mech'- anism drivenby said rope; a'limit switch; means driven 'by'the speed-reducing mechanism to actuate-thelimit switch; and means toad-just the .positionof the limit switch actuating means relative to the speed-reducing means,thereby to compensate for slippage of the rope relative to the speed-reducing mechanism- 1 l V 4.. A ltraversing'hoist comprising, in combination, a power-actuated traverse rope.

connected to the material-handlingelement' hoist; a speed-reducing of the traversing mechanisnrdriven by said rope; a limit.

- switch; means driven by'the speed-reducing mechanism to actuate the limit switch; means to adj ust the position of the limit switch actuating means relative to the speed-reducing means, thereby to compensate for slippage of the rope an indicator driven by the speedreducing mechanism and means to adjust for creepa-ge of the rope, said means also simultaneously adjusting the indicator because of 33 theconnection between the indicator and the mechanism aforesaid. 1

- 5. A mechanism for actuating limit switches and the like, comprising, in combination, a reduction gearing; a shaft driven at at a slow speedby the reduction gearing v and two disk-like cam members secured axially upon the sha-ftfto be rotated there being one cam associated with each'switch thereby to cause actuation of the two limit switches as'the shaft is rotated in opposite directions.

7. A mechanism. for

switches and the like, comprising, in combination, a reduction gearing; a shaft driven carried by the disk-like member, and .ar-'

at a slow speed by'the reduction gearing; two

like cam members secured upon the shaft to be rotated thereby tocause actuation of two different limit switches'as the shaft is rotated in opposite directions; nutsscrew-threaded upon oppositeends of the shaft; :and means clamped by the nuts t'oihold the cams in adjusted positions; r 1

8. A mechanism for actuating limit switches and the like, comprising, in combination, a reduction gearing;ashaftldriven at a slow speed bythe redu'ction gearing; a disk- I like member rotated by the shaft; an annulus provided upon the disk-like member; a cam ranged so as to actuate a limit switch once during each revolution of the disk-like. member; and means to adjust the annulus angu-V larly relative to the disk-like member.

i -9. A mechanism for actuating limit switches, and the like, comprising, in combination, a reduction gearing; a shaft driven ata slow speed by the reduction gearing; a

disk-like member rotated by the shaft; a'cam carried by the disk-like member, and arranged-so as toactuat-e'a limit switch once during each revolution of the disk-like member; an in dicatorfand power-transmitting means connecting the disk-like member andindicator sothat as the shaftrotates the indicator is moved correspondingly.

10. A 'traversinghoist comprising, in com- I to clamp the two parts together; and an bination, a motor; the pair of drums one driven by the motor, a second'being an idler drum on a countershaft; a traverse rope wound about both drums and driving the second drum; a'set of. lim1t switches connected in the motor circuit and actuated by the shaft of the second drum an indicator; connecactuating limit lar adjustment.

tions between the indicator and the limit switch. actuating means; "and means to adjust the-connectionsin the event of creepage of the traverse'rope'on the second drum. i 11. Atraversing hoist comprising, in combination, a speed-reducing mechanism; a

limit switch; means driven by the speed-reducing mechanism to actuate the limit switch;

said means including a cam, ashaft, and means to clamp the cam to the shaft, the shaft being driven at low speed by the speed reducing mechanism. V v v 12; A mechanism for actuating, limit switches and the like, comprising, in combination, a reduction gearing a shaft driven" at a slow speed bythe reduction gearing; a disk-like member rotated by the shaft; a cam carried by the disk-like member, and arranged so as to actuate a limit switch" once" duringeach revolution of the disk-like member; and means to press the disk-like memberforcefullyagainst the cam to clutch the cam theretofsaid means permitting any angular movement of the cam about the shaft as an axis to permit adjustment of the mechanism.-

13. The combination of a power drivenrope attached to a materials-handling device to move-' 'the same; a speed-reducing mechanism driven by the rope; an indicator; and means connecting said mechanism'with said indicator; said means having an adjustable part to which the'indicator is attached,

so that adjustment of the mechanism also sets the-indicator right. I 7 '14; An actuator-for limit switches and the 'li'ke :comprising, in combination, a power driven shaft provided with screw-threads;- a plate loosely'mounted on the shaft; a member secured'tothe shaft against rotation but movablelongitudin ally thereof; a'nut engaging with the screw-threads on the shaft and moving said member against the plate to clamp the two parts together; and an annulus mounted onxthe member and independently clamped thereto so as to permit angu- 15. 'Anactuator for limit switches and the like comprising, in combination, a power driven shaft provided with screw-threads; a plate'loosely mounted on the shaft and havoingjan annularbeveled surface; a member securedto the shaft against rotation'butmovable longitudinally thereof and having a beveled periphery to frictionally engage the beveledsurface on the plate; a nut en-' gaging with the screw-threads on the shaft 1 and moving said'member against the plate annulus mounted on the member and independently clamped thereto so ,asto permit angular adjustment, said annulus havinga grooved periphery tofreceive a' rope.

16. The combination of a traverse rope for a traversing hoist; a speed reducing mechanism driven directly from the rope; a traverse motor for driving said rope in opposite directions; a pair of limit switches in the motor circuit; limit switch actuating means driven from the speed-reducing means; and a solenoid brake for stopping the motor whenever the motor circuit is opened by one of the limit switches.

17. In combination, an electric, reversible motor having a solenoid brake; a drum driven by said motor; a second idler drum; a traverse rope wrapped about both drums and connected with the material-handling mem-' ber of a traversing hoist so as to move said member in opposite directions as the motor is reversibly driven; reduction gearing driven by said idler drum; a pair of limit switches in the motor circuit; and a pair of cams driven by said reduction gearing and actuating said limit switches alternately to stop the motor after predetermined rotation in opposite directions.

18. The combination of a rope for moving a material-handling element; a winding drum for moving the rope; an electric motor for driving said drum in opposite directions; a pair of limit switches in a motor-controlling circuit; a solenoid brake for'stopping the motor; a speed-reducing unit, comprising an a slow speed shaft and a disk on said shaft, driven by the motor; a pair of cams on the periphery of the disk and angularly adjustable with respect to the slow speed shaft of the speed-reducing unit; said cams being -25 moved, as the disk oscillates, into contact with the respective limit switches, thereby opening the motor circuit and causing the solenoid brake to stop the motor and drum, at or near the desired limits of travel of the re material-handling element.

In testimony, that I claim the foregoing as my own, I have hereto afiixed my signature.

HOWARD V. HARDING. 

